JACKSON, Mississippi -- A 20-year-old Jackson man is accused of gunning down his 49-year-old father and 74-year-old grandmother.

Tyrone Liddell Jr. was booked Thursday night and is being held without bond on two counts of murder in the deaths of Tyrone Liddell Sr. and Bertha Lee Liddell, Jackson Police Chief Lindsay Horton said Friday.

Liddell denied involvement as he was escorted out of court, WLBT-TV reported.

Horton said Liddell's mother helped police find her son after her husband and mother-in-law were killed in an apparent rage.

According to Horton, the witness said Liddell and his father were arguing Wednesday night, when the shootings apparently occurred Wednesday night. "We do not know at this point why or what caused him to discharge his firearm," Horton said.

The bodies were found about 7:40 a.m. Thursday.

The weapon was not found but Horton said the shell casings recovered at the scene were from a .40-caliber weapon.

"As of now, he is a lone suspect, and we are continuing the investigation," Horton said.